Iridium Flares over Australia
September 10th 2008 05:55
Enough with the mellow dramatics,
Technically I am not talking about a traditional flare as such. What I am referring too is more like seeing a light bouncing off a mirror. The Mirror happened to be a communication satellite, more like a series of satellites. A series of communication satellites were launched by the Iridium Corporation in 1998 to provide mobile phone (cell) communication worldwide.
Reports began coming in shortly after launch from a group of amateur satellite observers who were seeing some very bright reflections from these particular satellites in certain parts of the sky.
72 required satellites have been launched, and though a few are already dead for one reason or another, most are working fine. The working system consists of eleven satellites per plane in evenly spaced (30 degrees) planes currently orbiting the Earth at a height of around 780 kilometers.
Each satellite carries 3 antennas spaced 120 degrees apart, 188 cm wide x 86 cm long x 4 cm thick each are highly reflective aluminum flat plates treated with silver-coated Teflon for thermal control, makes one heck of a mirror.
The satellites are rotating once per orbit, so that the orientation relative to the local vertical is always the same. The main mission antennae (MMA) have a silver-coated Teflon surface of area about 1.6 square meters.
It is the antennas that cause the “flare” when sunlight hits the antenna at a predicted point in space. What we see is flash of light in the sky that may last for a few seconds.
The intensity of the “flare” does vary in magnitude some “fares” are very bright that they can be seen in daylight. Some peaking at magnitude -6, lasting for about 10 seconds.
The flashes can be quite bright especially in the night sky, some flashes are almost 4 times brighter than planet Venus. The” flash” average is about the size of a very bright star.
I have been trying to photograph them over the years with some success simply because the orbits of these satellites can be predicted; therefore you can set up a camera and tripod in advance.
Most of my photographs were shot using a wide angle DLSR camera at around ISO 800.
I have posted a few of my images taken over many months.
You can get very precise information on the net of where and when a particular satellite will seen in your area. A great site for predictions is http://heavens-above.com registration is free just open an account with your location details. By logging in you can see when an Iridium flare can be seen in your area.
Timing is critical go outside a few minutes before the “FLARE” is about to pass overhead this will give you time to get oriented, patience and good timing are the key factors.
The times and co ordinates are very precise, you may need a compass and an accurate time piece.
Some Iridium flares can be seen early in the morning some can be seen just after sunset.
Each Iridium satellite pass will differ in brightness some appear to be bright others might be harder to see because of Sun angle or orbit parameters. Be persistent and eventually you will get to see these amazing objects in the sky.
Images my be used in other articals provided that the copyrite holder is cited
Technically I am not talking about a traditional flare as such. What I am referring too is more like seeing a light bouncing off a mirror. The Mirror happened to be a communication satellite, more like a series of satellites. A series of communication satellites were launched by the Iridium Corporation in 1998 to provide mobile phone (cell) communication worldwide.
Reports began coming in shortly after launch from a group of amateur satellite observers who were seeing some very bright reflections from these particular satellites in certain parts of the sky.
A typical Iridium Satelite set up
72 required satellites have been launched, and though a few are already dead for one reason or another, most are working fine. The working system consists of eleven satellites per plane in evenly spaced (30 degrees) planes currently orbiting the Earth at a height of around 780 kilometers.
Actual Photo of a Iridium Salelite showing one of the 3 solar panels: Image credit D.Deak
Each satellite carries 3 antennas spaced 120 degrees apart, 188 cm wide x 86 cm long x 4 cm thick each are highly reflective aluminum flat plates treated with silver-coated Teflon for thermal control, makes one heck of a mirror.
It is the antennas that cause the “flare” when sunlight hits the antenna at a predicted point in space. What we see is flash of light in the sky that may last for a few seconds.
The intensity of the “flare” does vary in magnitude some “fares” are very bright that they can be seen in daylight. Some peaking at magnitude -6, lasting for about 10 seconds.
The flashes can be quite bright especially in the night sky, some flashes are almost 4 times brighter than planet Venus. The” flash” average is about the size of a very bright star.
I have been trying to photograph them over the years with some success simply because the orbits of these satellites can be predicted; therefore you can set up a camera and tripod in advance.
Most of my photographs were shot using a wide angle DLSR camera at around ISO 800.
I have posted a few of my images taken over many months.
Image Showing Iridium 5 the small dotted line seen below is an aircraft: image credit carlcan
Iridium 42 making a show in the night sky' : image credit carlcan
Although on this particular orbit Iridium 6 was not very bright you can still see it
In contrast Iridium 56” Flare” is quite bright, most of the “flares” appear in around the same relative space in the sky. : image credit carlcan
On this occasion Iridium 35 was rather dim you can just make the “white” line track in this time exposure: image credit carlcan
You can get very precise information on the net of where and when a particular satellite will seen in your area. A great site for predictions is http://heavens-above.com registration is free just open an account with your location details. By logging in you can see when an Iridium flare can be seen in your area.
Timing is critical go outside a few minutes before the “FLARE” is about to pass overhead this will give you time to get oriented, patience and good timing are the key factors.
The times and co ordinates are very precise, you may need a compass and an accurate time piece.
Some Iridium flares can be seen early in the morning some can be seen just after sunset.
Each Iridium satellite pass will differ in brightness some appear to be bright others might be harder to see because of Sun angle or orbit parameters. Be persistent and eventually you will get to see these amazing objects in the sky.
Images my be used in other articals provided that the copyrite holder is cited
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Comment by S.L.
The Political Brief
Comment by CarlCan
Astroearth
Thanks again for the comment. Iridium Flares are interesting object to see. Perhaps at a later date I will have some on video.
I will look into perhaps writing some articles for bright Hub in the near future.
Cheers
Carl